A prospective cohort study that was conducted by Mohamed Farag et al. in European Heart Journal demonstrated that evaluating endogenous fibrinolysis in patients with acute coronary syndrome may help physicians identify high-risk patients developing recurrent cardiovascular events, especially among those treated with dual antiplatelet therapy (DAT) after primary percutaneous coronary intervention (PPCI).
Based on current guidelines, patients with acute coronary syndrome who meet the criteria should receive PPCI followed by DAT to reduce the risk of developing further cardiovascular complications. Although this recommendation helps to prevent cardiovascular events in the majority of patients, 15% of patients experience a major adverse cardiovascular event (MACE). It has been shown that the majority of these patients have impaired endogenous thrombolysis, which leads to a more firm thrombotic plaque and increases the risk of MACE development. Early identification of these individuals can help to decrease the rate of MACE in these predisposed patients. Farag et al. raised this question whether measurement of endogenous fibrinolysis could help determine the risk of developing MACE in patients with previous PPCI.
Farag et al. conducted a single-center prospective observational study on 80 patients who underwent PPCI and received DAT with aspirin and either clopidogrel or ticagrelor. They evaluate patients blood for platelet reactivity and endogenous fibrinolysis from native, non-anticoagulated blood 3 times, at hospitalization, near discharge when the patient was stabilized, and at 30 days follow up. The laboratory technique they used helped in determining the time it took to form an occlusive thrombus under high-shear stress (occlusion time, OT) as well as the time required to restore flow through endogenous fibrinolysis (lysis time, LT).
They showed a statistically significant relationship between developing MACE and the following patients characteristics: age, prior MI, prior PCI, prior stroke, prior statin, prior aspirin, cardiogenic shock, TIMI score, low haemoglobin, low haematocrit, low albumin, high creatinine, high C-reactive protein, short baseline OT, number of diseased vessels on angiography, left ventricular dysfunction, and absence of spontaneous ST-resolution pre-PPC. They demonstrated that baseline LT >_ 2500 s was significantly predictive of MACE after adjustment for other risk factors. The result of their study showed that patients who experienced spontaneous reperfusion had a shorter baseline LT and longer baseline OT compared to patients who did not experience spontaneous reperfusion.
The investigators concluded that significantly impaired endogenous fibrinolysis in 14% of patients may be considered as a predictive factor of recurrent MACE. It was previously shown that non-vitamin K antagonist oral anticoagulants (NOACs), rivaroxaban, and PAR-1 inhibitor vorapaxar could help improve endogenous fibrinolysis. Investigators addressed their study limitation of having a small sample size and conducting the study in a single center and recommend repeating the study with a larger sample population.